1. Field of the Invention
The present invention relates to a method and apparatus for finalizing a dual layer recording medium.
2. Background of the Related Art
As broadcast channels including terrestrial, cable, satellite TV, etc. are diversified, it is frequent that a user records a program to watch into a disc medium which is a digital recording medium by reserved recording and watches the program at his/her convenience. Since data bit rate becomes about 9.8 Mbps when broadcast signals are recorded in high video quality (HQ mode), a widely used recording medium such as DVD+/−R with recording capacity of 4.7 GByte can record a broadcast program lasting an hour or so (approximately 64 minutes).
However, since it is quite often the case that a broadcast program lasts more than 60 minutes and a user may want reserved recording of more than two broadcast programs in high video quality mode, the capacity of a recording medium as above may be regarded to be insufficient for high video quality recording of a broadcast program.
Recently, a dual layer disc medium has been developed and commercialized, where double recording layers are set up on one side of a disc medium so that the recording capacity should be significantly increased.
By the way, after a broadcast program having been recorded on a dual layer disc medium, the disc medium may be taken away from a recording apparatus used for recording the broadcast program and reproduced by a playback-only disc player. For example, after a broadcast program having been recorded on a recording medium through a recording apparatus installed in a living room, the broadcast program recorded on the recording medium can be reproduced by a playback-only disc player installed in a place other than the living room, e.g., a bedroom.
As mentioned above, in order for a playback-only disc player to be able to reproduce a disc medium where a broadcast program has been recorded by a recording apparatus, finalization must be carried out on a recordable disc medium. Finalization is an operation duplicating information located in PMA area into a lead-in area, where the information is used for managing respective recording sections recorded in a recordable disc medium by a recording apparatus as respective logical tracks, and recording data intended for signals of 2 kHz to be detected at the outer circumference of the last recording section, thereby creating a lead-out area. A playback-only disc player can reproduce a recordable disc medium finalized as described above.
A playback-only disc player, e.g., DVD player, before reproducing a loaded disc medium, focuses the beam of an optical pickup on an arbitrary point within a radius of 4 cm considering the possibility of insertion of a disc medium having a diameter of 8 cm and adjusts servo characteristics based on the characteristics of RF signals detected by the beam focusing. If RF signals are not detected and subsequent servo characteristics are not set up properly, playback of a loaded disc medium will not be made possible.
Therefore, in order to reproduce a recordable disc medium in a DVD player, the interior of the disc medium having a diameter of 8 cm must have arbitrary data recorded for RF signals to be detected other than left in blank state. As a consequence, upon the request from a user requiring finalization of a dual layer disc medium for reproduction in a DVD player, a recording apparatus of a disc medium, besides the finalization operation above, as shown in FIG. 1, carries out an operation of padding null data in double layers except for a recorded data section 100. In other words, as shown in FIG. 1, if finalization request is issued when only a part of a first recording layer 1a contains recorded data 100, the entire area 1b of a second recording layer is padded with null data. In the case of a single-layer disc medium, if data are not recorded up to a radius of 4 cm, null data are padded to the area of radius of 4 cm and finalization is completed.
Since the operation of padding null data is the same process as data recording operation, however, considerable time is needed in the case of a dual layer disc medium; as a data section in a recording layer of a disc medium recorded by a user's request becomes small, much more time is needed to complete finalization. Such a long time requirement needed for finalization imposes severe inconvenience on a user who wants to watch a recorded program in another playback apparatus.